DRILL TOOL FOR METAL-WORKING MACHINES AND METHOD OF ITS FABRICATION Russian patent published in 2012 - IPC B23B51/02 B23P15/32 

FIELD: process engineering.

SUBSTANCE: proposed method comprises turning drill body from parent metal to make first blank symmetric about rotational axis. Two deep spaced apart holes are drilled in first blank to extend from blank end points arranged off-center relative to central axis 34 toward cutting head shank. Second blank thus made to have spaced apart clamp points in zone located there between is heated to preset temperature and coiled by plastic deformation at preset angle. Chip removal flutes milled in third blank in helical fashion in amount matching with that of said deep holes so that coiled deep holes extends inside fluted lands. Note that deep holes are milled on cutting head side in untwisted straight area to make outlet holes extending into chip removal flutes.

EFFECT: simplified production.

19 cl, 4 dwg